1. Field of the Invention
The invention relates to a data carrier, which data carrier is provided and designed for contactless communication with a communication station and for this purpose comprises receiving means for receiving a request signal, which request signal can be generated by a communication station and can be transmitted to the data carrier in a contactless manner with the aid of a field generated by the communication station and acting on the data carrier, wherein the data carrier comprises storage means for storing at least two items of status information of significance for the data carrier, and readout means for reading out, in each case, one stored item of status information in response to receiving the request signal, and processing means for processing the status information read out in each case, which processing means process the status information read out in each case to create a transmission signal suitable for transmission to the communication station, and in which processing means at least one transmission parameter for the transmission signal can be altered.
The invention further relates to a circuit for a data carrier for contactless communication with the communication station, which circuit comprises connection means for receiving a request signal and storage means for storing at least two items of status information of significance for the data carrier, and readout means for reading out, in each case, one stored item of status information as a result of receiving the request signal, and processing means for processing the status information read out in each case.
The invention further relates to a communication station for contactless communication with a data carrier having the design described above in the first paragraph.
2. Description of Related Art
A data carrier with the design described above in the first paragraph with a circuit having the design described above in the second paragraph has been marketed by the applicant and is therefore known. Among the applications of the known data carrier, there is one in which the known data carrier or a plurality of known data carriers of this kind are part of a so-called electronic article surveillance system (EAS system). In an electronic article surveillance system of this kind, a data carrier is in each case attached to an article to be subjected to surveillance, for example to an item of clothing or a device in the field of entertainment electronics, or one of many other products. A so-called EAS bit configuration may here remain in its original status or be set for a new status, which results in either a first EAS bit configuration or a second EAS bit configuration being stored in storage means of the known data carrier, whereby the first EAS bit configuration forms a first item of status information of significance for the data carrier and the article to which the data carrier is attached, and the second EAS bit configuration forms a second item of status information of significance for the data carrier and the article to which the data carrier is attached. In a known embodiment, the first EAS bit configuration, which forms the first item of status information, is formed by the bit xe2x80x9c1xe2x80x9d, and the second EAS bit configuration, which forms the second item of status information, is formed by the bit xe2x80x9c0xe2x80x9d. Many other bit configurations with a higher number of bits are, of course, also possible. The first EAS bit configuration, i.e. the bit xe2x80x9c1xe2x80x9d, is set, in the known system, when the decision is made that the data carrier is to serve for electronic article surveillance, in which case the setting takes place in a contactless manner with the aid of a communication station. The second EAS bit configuration, i.e. the bit xe2x80x9c0xe2x80x9d, is set, in the known system, when the price for the article to which a data carrier is attached has been paid at a cash point, whereby provision is made for the setting of the second EAS bit configuration in a contactless manner at the cash point with the aid of a communication station located there. If, on the other hand, no payment has been made of the price of an article to which a data carrier is attached, the first EAS bit configuration remains stored in the storage means of the data carrier, which causes the first EAS bit configuration originally set to be retained unchanged.
In the known electronic article surveillance system, the design is executed in such a way that, when an article with a data carrier attached to the article passes through a checking station, a communication station contained in the checking station emits an EAS scanning command as a request signal to the data carrier attached to the article, whereby, disadvantageously, only in the event that the first EAS bit configuration, which indicates that the price for the article in question has not been paid, is stored in the data carrier does the data carrier transmit to the communication station a transmission signal, created to take account of the first EAS bit configuration, in the form of a pre-specified, fixed bit pattern, at a fixed time. In the known system, an effect at the communication station side, for example a visual or acoustic warning indication, brought about by an EAS bit configuration stored in a data carrier, i.e. an item of status information, can therefore be derived only from a recognition of the transmission signal created on the basis of the first EAS bit configuration, which means that an effect of this kind can be initiated only upon recognition of an article for which no payment has been made. In the known solution, therefore, only one single item of status information of significance for a data carrier is ever transmitted to a communication station with the aid of a transmission signal with a specific transmission parameter, specifically always at a fixed time, i.e. always in the same time slot. This represents a limitation that has proved a disadvantage in many application cases.
It is an object of the invention to eliminate the above-cited limitation, and to realize an improved data carrier and an improved circuit for a data carrier and an improved communication station.
To achieve the above-cited object, features according to the invention are provided in a data carrier according to the invention, so that a data carrier according to the invention can be characterized as follows.
Data carrier for contactless communication with a communication station, which data carrier comprises the means listed below: receiving means for receiving a request signal, which request signal can be generated by a communication station and can be transmitted to the data carrier in a contactless manner with the aid of a field generated by the communication station and acting on the data carrier, and storage means, which storage means are designed for storing at least two items of status information of significance for the data carrier, and readout means for reading out one stored item of status information at a time as a result of receiving the request signal, and processing means for processing the status information read out in each case, which processing means are designed for processing the status information read out in each case so as to create a transmission signal suitable for transmission to the communication station, and in which processing means at least one transmission parameter for the transmission signal can be altered, and recognition means for recognizing the status information read out in each case, and control connection means between the recognition means and the processing means, which control connection means are designed to have a controlling effect on the processing means as a function of the status information recognized and read out in each case, specifically to alter the at least one transmission parameter for the transmission signal as a function of the status information recognized and read out in each case.
In order to achieve the above object, features according to the invention are provided in a circuit according to the invention, so that a circuit according to the invention can be characterized as follows.
Circuit for a data carrier for contactless communication with a communication station, which circuit is equipped with the means listed below: connection means for receiving a request signal, which request signal can be generated by a communication station and can be transmitted to the data carrier, and consequently to the circuit for the data carrier, in a contactless manner with the aid of a field which is generated by the communication station and acts on the data carrier, and storage means, which storage means are designed for storing at least two items of status information of significance for the data carrier, and readout means for reading out one item of stored status information in each case as a result of receiving the request signal, and processing means for processing the status information read out in each case, which processing means are designed for processing the status information read out in each case so as to create a transmission signal suitable for transmission to the communication station, and in which processing means at least one transmission parameter for the transmission signal can be altered, and recognition means for recognizing the status information read out in each case, and control connection means between the recognition means and the processing means, which control connection means are designed to have a controlling effect on the processing means as a function of the status information recognized and read out in each case, specifically to alter the at least one transmission parameter for the transmission signal as a function of the status information recognized and read out in each case.
The provision of the features according to the invention, achieves in a simple manner and with only a small additional outlay that the creation of the transmission signal suitable for transmission to a communication station is enabled as a function of several items of status information of this kind, and this takes place here as a function of the status information read out in each case, so that, from several items of status information possibly stored in a data carrier, one item of status information can be transmitted in each case to a communication station in an advantageous manner with a transmission parameter selected for the status information concerned. The provision of the measures according to the invention, achieves in an advantageous manner that, in the case of a high number of groups of data carriers, in which groups it is anticipated per se that a specific item of status information will be present among all the data carriers of each group, in the event that, in a group of this kind, a data carrier does not contain the status information anticipated to be in it, this group can be recognized very quickly, following which this group of data carriers can be separated in a simple manner from the remaining groups of data carriers, whereupon finally the data carrier in which a non-anticipated item of status information is stored can be pinpointed among the remaining data carriers of this group, various methods being possible for this pinpointing, although this is not relevant in the present context. It is also achieved in an advantageous manner through the measures according to the invention that information can be obtained in a communication station in a simple manner as to whether at least one data carrier is present in specific possible groups of data carriers, in which the data carriers of each group have a specific item of status information in store. It is further advantageously achieved through the measures according to the invention that the presence of a so-called mixed population of data carriers in a communication field of a communication station can be recognized very simply and rapidly.
In a data carrier according to the invention and in a circuit according to the invention, it has proved particularly advantageous if, in addition, the features as claimed in claim 2 and claim 7, respectively, are provided. A design of this kind is particularly advantageous because the control means, which are capable of generating control data, render possible a high diversity in relation to the control of the processing means as a function of the status information recognized and read out in each case, if so desired. It should, however, be mentioned at this point that, in the simplest case, it is possible to proceed even without provision of the control means, in which case control connection means formed by simple electrical or electronic connections are provided between the recognition means and the processing means, which control connection means can feed control commands emitted by the recognition means directly to the processing means.
In a data carrier according to the invention and in a circuit according to the invention, it has proved advantageous if, in addition, the features as claimed in claim 3 and claim 8, respectively, are provided. A design of this kind has the advantage that the processing of a recognized, read-out item of status information for creating a transmission signal takes place as a function of the recognized, read-out item of status information in a time window starting at a specific occurrence point.
It has also proved advantageous if, in the case of a data carrier according to the invention and a circuit according to the invention, the features as claimed in claim 4 and claim 9, respectively, are additionally provided. It is hereby achieved in a simple manner that the type of coding undertaken in the course of the processing of a recognized, read-out item of status information for creating a transmission signal is chosen as a function of the recognized, read-out item of status information, so that the coding type chosen in each case depends on the recognized, read-out item of status information.
In a data carrier according to the invention and in a circuit according to the invention, it has, however, also proved extremely advantageous if the features as claimed in claim 5 and claim 10, respectively, are additionally provided. A design of this kind provides the advantage that the sub carrier that may be required for processing a recognized, read-out item of status information for creating a transmission signal can be matched to the recognized, read-out item of status information in respect of its sub carrier frequency.
In order to achieve the above-cited object, features according to the invention are provided in a communication station according to the invention, so that a communication station according to the invention can be characterized as follows.
Communication station for contactless communication with a data carrier, which data carrier is designed for contactless communication with the communication station and comprises the means listed below: receiving means for receiving a request signal, which request signal can be generated by the communication station and can be transmitted to the data carrier in a contactless manner with the aid of a field created by the communication station and acting on the data carrier, and storage means, which storage means are designed for storing at least two items of status information of significance for the data carrier, and readout means for reading out, in each case, one stored item of status information as a result of receiving the request signal, and processing means for processing the status information read out in each case, which processing means are designed to process the status information read out in each case so as to create a transmission signal suitable for transmission to the communication station, and in which processing means at least one transmission parameter for the transmission signal can be altered, and recognition means for recognizing the status information read out in each case, and control connection means between the recognition means and the processing means, which control connection means are designed to have a controlling effect on the processing means as a function of the status information recognized and read out in each case, specifically to alter the at least one transmission parameter for the transmission signal as a function of the status information recognized and read out in each case, said communication station comprising the following means: command-signal generating means for generating command signals and receiving means for receiving the transmission signal transmitted to the communication station by the data carrier, and processing means for processing the received transmission signal, and transmission-parameter recognition means for recognition of the transmission parameter of the received transmission signal, and decision means which cooperate with the transmission-parameter recognition means and which are provided and designed to make a decision concerning the generation of at least one command signal as a function of the transmission parameter of the received transmission signal recognized by the transmission-parameter recognition means.
The provision of features according to the invention, achieves in simple manner and with only a small additional outlay in a communication station according to the invention that the generation of specific command signals is permitted or cleared by the decision means only if a specific item of status information is stored in the particular data carrier that is the cause of the command signals being generated, which has been established by the recognition means in the data carrier and which has ultimately influenced the transmission parameter of the transmission signal from the data carrier to the communication station. It is thereby made possible, in a simple and advantageous manner that, for example, in the case of electronic article surveillance system with a communication station according to the invention, a specific display command signal is generated for a display device by a host computer of the article surveillance system only if the status information corresponding to, i.e. matching, this specific display command signal is stored in the article-surveillance data carrier.
In the case of a communication station according to the invention, it has proved especially advantageous if, in addition, the features as claimed in claim 12 are provided. By this means it is made possible in a simple, advantageous manner, for example, that a specific command signal for a data carrier is generated by the command-signal generating means of the communication station according to the invention only if an item of status information is stored in the data carrier concerned for which the execution of a procedure that can be initiated by the specific command signal is appropriate.